Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS4129679 A
Publication typeGrant
Application numberUS 05/511,434
Publication dateDec 12, 1978
Filing dateOct 2, 1974
Priority dateNov 27, 1969
Publication number05511434, 511434, US 4129679 A, US 4129679A, US-A-4129679, US4129679 A, US4129679A
InventorsCalvin R. Woodings
Original AssigneeCourtaulds Limited
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Multi-limbed regenerated cellulose filaments
US 4129679 A
Abstract
Highly absorbent regenerated cellulose filaments have a collapsed hollow structure, a multi-limbed cross-section and a water imbibition of 170 to 345 per cent. They are made by a viscose process using sodium carbonate as an inflating agent.
Images(1)
Previous page
Next page
Claims(2)
What is claimed is:
1. A bundle of highly absorbent, regenerated cellulose filaments, substantially all of the filaments of said bundle having a collapsed hollow structure, and at least 60 percent of said filaments comprising in cross-section at least three elongated limbs extending from a common origin, the water imbibition of said bundle being from 170 to 345 percent.
2. A bundle of regenerated cellulose filaments as claimed in claim 1 in which the filaments have a count in the range 0.5 to 10 d.Tex.
Description

This application is a continuation of my prior application Ser. No. 280,113 filed Aug. 14, 1972, and now abandoned which itself is a continuation-in-part of my prior application Ser. No. 92,799 filed Nov. 25, 1970 and now abandoned.

This invention relates to multi-limbed filaments of regenerated cellulose, and to a process for making them from viscose.

In the viscose art, there have been various proposals for making hollow regenerated cellulose filaments by inflating the filaments during regeneration using a material dispersed in the viscose which is either a gas, or a solid which releases a gas on contact with the spin bath. Alkali carbonates, particularly sodium carbonate, are the most commonly used inflation materials. The type of hollow structure aimed at has varied and early efforts were directed at making tubular or cellular structures in which the filament stayed inflated to provide a bulky, low density yarn giving good cover in fabrics made from it. Filaments of this type are described in U.S. Pat. Nos. 2,476,293 and 2,835,551 (cellular) and Japanese Pat. No. 40-9064 (tubular).

More recently, there has been interest in making inflated filaments which collapse upon themselves to form flat filaments which, because of this flat shape, bond to each other strongly by hydrogen bonding; this characteristic makes them very suitable as paper-making fibres. Filaments of this type are described in British Pat. No. 945,306 and U.S. Pat. Nos. 3,156,605 and 3,318,990. Another interesting characteristic of these filaments is their high water absorbency, which surprisingly, is higher than that of inflated tubular filaments. For example, the flat filaments (British Pat. No. 945,306) and the hollow filaments (U.S. Pat. No. 3,626,045) made by Courtaulds Limited have water imbibitions which average about 140 percent and 125 percent respectively. Unfortunately, the self-bonding property which makes the flat filaments so useful in paper-making, is detrimental to their use in absorbent textile products because it makes them virtually unprocessable; thus, they bond to each other on being dried after wet processing and prevent, say, satisfactory carding.

It is an object of this invention to provide regenerated cellulose filaments which have an even higher water absorbency, and which can be processed satisfactorily, by a modified viscose process.

This invention resides in a bundle (by which is meant a tow comprising at least 10,000 filaments or a collection of at least the same number of staple fibres cut from such a tow) of highly absorbent, regenerated cellulose filaments, substantially all of the filaments of said bundle having a collapsed hollow structure, and at least 60 percent of said filaments comprising in cross-section at least three elongated limbs extending from a common origin, the water imbibition of said bundle being from 170 to 345 percent. The collapsed hollow structure confers high absorbency on the filaments, which swell as they absorb water, revealing their hollow structure when examined in cross-section. The multi-limbed cross-section, which is retained even after swelling, allows the filaments to be processed by the usual fibre and textile processing methods, and in addition confers an even greater absorbency on products made from the filaments by virtue of the capacity of the filament bundle to hold large quantities of interstitial water between adjacent limbs of the filaments. The filaments have a high bulk and a cotton-like handle, and they have a dull matt appearance even without pigmentation because the multi-limbed cross-section causes scattering of reflected light. In the bundle of filaments, various cross-sections will be obtained including roughly Y-, X- and H- shapes and more complicated shapes.

The FIGURE is a reproduction of a photograph of a cross-section of a tow of filaments according to the invention as produced by the process specifically described in Example 2 below.

The bundle of filaments of the invention may be made by a viscose process using sodium carbonate as the inflating agent. The process conditions are selected so that the inflation process and the regeneration process are balanced to produce the desired structure. Thus, sufficient inflation is permitted so that the filament can subsequently collapse, but this is balanced by having a sufficiently strong regeneration reaction to form a skin on the inflating filaments which is thick enough to prevent too much inflation with subsequent collapse to a flat structure.

Virtually any commercial viscose may be used, and the majority have a cellulose content of 6.5 to 12 percent by weight and a caustic soda content of 4 to 10 percent. It is important, however, that the spinning viscose should have a low salt figure in the range 3.5 to 5.1. At higher salt figures, a spun tow would have an increasing percentage of flat filaments as the salt figure was raised above 5.1 until at a salt figure of about 7 the tow would be virtually all flat filaments. The ball fall viscosity of the viscose is usually in the range 30 to 180 seconds at 18 C. The amount of sodium carbonate in the viscose should be in the range 2 to 5 percent by weight. Insufficient inflation would be achieved with less, in view of the comparatively thick skin formed during regeneration.

The spin bath may be a conventional bath having a low zinc sulphate content or even no zinc sulphate; a range of 0 to 3 percent by weight is suitable. The sulphuric acid concentration may be within wide limits, 9 to 20 percent by weight but is preferably nearer the lower end of the range. 20 to 26 percent by weight of sodium sulphate is a suitable range.

The temperature of the spin bath is unusually high for making inflated filaments, 60 C. to 85 C., and is designed to produce the desired skin thickness during regeneration so as to avoid too great an inflation. As the temperature is lowered below 60 C., an increasing amount of flat fibre is produced.

The spun filaments may be subjected to the usual washing and stretching operations, preferably being stretched at least 10 percent in a hot, dilute aqueous sulphuric acid bath, for example 2 percent by weight at a temperature of 95 C. For most end-uses, stretching up to about 70 percent is sufficient to give adequate filament strength. The process is most efficient when producing filaments of count 0.5 to 10 dTex.

Within the ranges specified above, in general the conditions for producing the bundle of multi-limbed filaments of the invention, move away from the optimum as the salt figure of the viscose is raised, as the zinc sulphate concentration of the spin bath is increased, and as the temperature of the spin bath is lowered. These shifts in conditions can be compensated for by lowering the concentration of the sodium carbonate in the viscose or by lowering the sulphuric acid concentration in the spin bath. Also, an increased salt figure can be compensated for by raising the spin bath temperature. The sodium carbonate and sulphuric acid concentrations are interdependent because at lower acid concentrations, more sodium carbonate is lost in the spin bath so that a greater initial concentration is required for comparable inflation with that at higher acid concentrations. Economic factors affect the chosen conditions, with lower acid and sodium carbonate concentrations being preferred for this reason. Similarly, it is preferred not to operate at the higher end of the spin bath temperature range, and about 70 C. is the preferred norm.

The bundle of multi-limbed filaments of the invention is capable of a wide application of use, both in staple fibre and continuous filament form, and particularly in end-uses which take advantage of its high water imbibition. These include woven fabrics like towelling and non-woven fabrics and waddings such as diapers, sanitary napkins, tampons and swabs. Conventional textile end-uses may benefit from the good cover and high bulk provided by the filaments at low basis weight. In staple fibre form, the filaments may be made into soft, bulky paper which is highly absorbent by mixing them with the flat, regenerated cellulose fibres referred to in British Pat. No. 945,306 or with conventional wood-pulp paper-making fibres.

The invention is illustrated by the following Examples in which percentages are by weight except for stretches.

EXAMPLE 1

A viscose comprising 7.85 percent cellulose, 5.23 percent caustic soda and 2.55 percent sodium carbonate, and with a salt figure of 3.8 and a ball fall viscosity of 35 seconds at 18 C., was extruded into an aqueous spin bath comprising 13.5 percent sulphuric acid, 0.8 percent zinc sulphate, 24.0 percent sodium sulphate and 61.7 percent water to form a tow of filaments having an average count of 1.7 d.Tex.

The temperature of the spin bath was 70 C. and the immersion path length was 24 inches. The spinning speed was 30 meters per minute. The spun tow of filaments was stretched by 30 percent in a 2 percent aqueous sulphuric acid stretch bath at a temperature of 95 C. and then the filaments were washed.

The filaments of the tow were predominantly of multi-limbed cross-section specified with a small proportion of filaments having the round cross-section of conventional regenerated cellulose filaments.

The filaments had an average water imbibition of 170 percent. The water imbibition was measured by taking a 1 gm. sample of the fibre, soaking it in water at a temperature of 20 C. for 15 minutes, centrifuging it at a force of 1000 g for 5 minutes, weighing it, drying it at a temperature of 110 C. for 2.5 hours, and finally re-weighing it. The percentage water imbibition is then equal to: ##EQU1##

EXAMPLE 2

A viscose comprising 8.05 percent cellulose, 5.28 percent caustic soda and 2.54 percent sodium carbonate, and with a salt figure of 5.1 and a ball fall viscosity of 30 seconds at 18 C., was extruded into an aqueous spin bath comprising 13.55 percent sulphuric acid, 0.7 percent zinc sulphate and 23.0 percent sodium sulphate to form a tow of filaments having an average count of 2.65 d.Tex.

The temperature of the spin bath was 66 C. and the immersion path length was 24 inches. The spinning speed was 30 meters per minute. The spun tow of filaments was stretched by 25 percent and washed.

The filaments of the tow were of the specified multi-limbed cross-section and had the specific appearance shown in the drawing. They had an average water imbibition of 220 percent.

EXAMPLE 3

A viscose comprising 7.45 percent cellulose, 5.08 percent caustic soda and 2.4 percent sodium carbonate, and with a salt figure of 4.1 and a ball fall viscosity of 31 seconds at 18 C., was extruded into an aqueous spin bath comprising 13.5 percent sulphuric acid, 0.8 percent zinc sulphate, 23.5 percent sodium sulphate to form a tow of filaments having an average count of 2.5 d.Tex.

The temperature of the spin bath was 70 C. and the immersion path length was 24 inches. The spinning speed was 30 meters per minute. The spun tow of filaments was stretched by 25 percent and washed.

The filaments of the tow were of the specified multi-limbed cross-section and had an average water imbibition of 280 percent.

EXAMPLE 4

A viscose comprising 7.86 percent cellulose, 5.08 percent caustic soda and 3.4 percent sodium carbonate, and with a salt figure of 5.0 and a ball fall viscosity of 28 seconds at 18 C., was extruded into an aqueous spin bath comprising 10.5 percent sulphuric acid, 0.8 percent zinc sulphate and 24.0 percent sodium sulphate to form a tow of filaments having an average count of 2.75 d.Tex.

The temperature of the spin bath was 72 C. and the immersion path length was 24 inches. The spinning speed was 30 meters per minute. The spun tow of filaments was stretched by 25 percent and washed.

The filaments of the tow were of the specified multi-limbed cross-section and had an average water imbibition of 310 percent.

EXAMPLE 5

A viscose comprising 7.2 percent cellulose, 4.9 percent caustic soda and 3.0 percent sodium carbonate, and with a salt figure of 4.1 and a ball fall viscosity of 28 seconds at 18 C., was extruded into an aqueous spin bath comprising 13.5 percent sulphuric acid, 0.8 percent zinc sulphate and 24.0 percent sodium sulphate to form a tow of filaments having an average count of 2.5 d.Tex.

The temperature of the spin bath was 70 C. and the immersion path length was 24 inches. The spinning speed was 30 meters per minute. The spun tow of filaments was stretched by 25 percent and washed.

The filaments of the tow were of the specified multi-limbed cross-section and had an average water imbibition of 345 percent.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2492425 *Aug 25, 1945Dec 27, 1949American Viscose CorpSpinning artificial filaments
US2835551 *Mar 29, 1956May 20, 1958Toyo Rayon Co LtdProcess for producing hollow viscose filaments
US3156605 *Mar 25, 1960Nov 10, 1964Fmc CorpRegenerated cellulose fiber
US3626045 *Dec 15, 1969Dec 7, 1971Coustaulds LtdProcess for making tubular filaments
US3670069 *Sep 15, 1969Jun 13, 1972IttProcess for forming hydroxyethyl cellulose fibers having high water absorption and high water retention properties
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4242411 *Mar 26, 1979Dec 30, 1980International Paper CompanyHigh crimp, high strength, hollow rayon fibers
US4355075 *Mar 24, 1980Oct 19, 1982Teijin LimitedNovel filament-like fibers and bundles thereof, and novel process and apparatus for production thereof
US5270509 *Dec 24, 1991Dec 14, 1993Electric Power Research InstituteMicrowave clothes drying system and method with improved arc detection
US5314743 *Dec 17, 1990May 24, 1994Kimberly-Clark CorporationNonwoven web containing shaped fibers
US5342336 *Mar 16, 1992Aug 30, 1994Kimberly-Clark CorporationAbsorbent structure for masking and distributing a liquid
US5458835 *Jul 22, 1994Oct 17, 1995Courtaulds PlcProcess of making viscose staple fibers
US5458963 *Nov 16, 1994Oct 17, 1995Kimberly-Clark CorporationNonwoven web containing shaped fibers
US5634914 *Apr 25, 1995Jun 3, 1997Courtaulds PlcCellulosic fibre
US5750446 *Dec 22, 1995May 12, 1998Mcneil-Ppc, Inc.Absorbent body
US6103376 *Aug 15, 1997Aug 15, 2000Eastman Chemical CompanyBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
US6333108 *May 9, 1995Dec 25, 2001Acordis Kelheim GmbhCellulose fibre compositions
US6342299Nov 23, 1999Jan 29, 2002Clemson University Research FoundationBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
US6352664Nov 16, 1999Mar 5, 2002Clemson University Research FoundationProcess of making a bundle of synthetic fibers
US6352774Nov 22, 1999Mar 5, 2002Clemson University Research FoundationBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
US6387493Nov 15, 1999May 14, 2002Clemson University Research FoundationBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
US6403217Oct 20, 2000Jun 11, 2002Clemson University Research FoundationBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
US6426140Oct 20, 2000Jul 30, 2002Clemson University Research FoundationBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
US6433246Dec 22, 1995Aug 13, 2002Mcneil-Ppc, Inc.Tampon having improved early expansion characteristics
US6436518Oct 20, 2000Aug 20, 2002Clemson University Research FoundationBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
US6451428Oct 20, 2000Sep 17, 2002Clemson University Research FoundationBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
US6465096Oct 20, 2000Oct 15, 2002Clemson University Research FoundationBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
US6468653Oct 20, 2000Oct 22, 2002Clemson University Research FoundationBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
US6492023Oct 20, 2000Dec 10, 2002Clemson University Research FoundationBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
US6495256Oct 20, 2000Dec 17, 2002Clemson University Research FoundationBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
US6497955Oct 20, 2000Dec 24, 2002Clemson University Research FoundationBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
US6509093Oct 20, 2000Jan 21, 2003Clemson University Research FoundationBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use bundles
US6610402Jul 2, 2001Aug 26, 2003Clemson University Research FoundationBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
US6617025Oct 20, 2000Sep 9, 2003Clemson University Research FoundationBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
US6748634 *Jun 4, 2002Jun 15, 2004Mcneil-Ppc, Inc.Tampon having improved early expansion characteristics
US6761957Nov 18, 1999Jul 13, 2004Clemson University Research FoundationBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
US7998313 *Nov 8, 2007Aug 16, 2011Georgia-Pacific Consumer Products LpInflated fibers of regenerated cellulose formed from ionic liquid/cellulose dope and related products
US8287785Oct 16, 2012Lenzing AktiengesellschaftProcess for the manufacture of solid regenerated viscose fibers
US20030055391 *Jun 4, 2002Mar 20, 2003Hien NguyenTampon having improved early expansion characteristics
US20030114068 *Dec 13, 2002Jun 19, 2003Clemson University Research FoundationArticle of manufacture useful as wallboard and a method for the making thereof
US20050179165 *Jan 5, 2005Aug 18, 2005Josef SchmidtbauerProcess for the manufacture of solid regenerated viscose fibres
US20060200103 *Sep 27, 2005Sep 7, 2006Josef SchmidtbauerSolid regenerated standard viscose fibres
US20080135193 *Nov 8, 2007Jun 12, 2008Georgia-Pacific Consumer Products LpInflated filbers of regenerated cellulose formed from ionic liguid/cellulose dope and related products
US20110200783 *Aug 18, 2011Lenzing AktiengesellschaftCellulosic staple fiber and its use
US20130189474 *Dec 21, 2012Jul 25, 2013Lenzing AktiengesellschaftCellulosic staple fiber and its use
CN103938290A *Feb 28, 2014Jul 23, 2014苏州恒光化纤有限公司Preparation method of hollow staple fiber
EP0301874A1 *Jul 29, 1988Feb 1, 1989Courtaulds PlcCellulosic fibre
EP0716170A2 *Dec 6, 1995Jun 12, 1996Courtaulds Fibres (Holdings) LimitedTampon production
EP1111098A2 *Aug 19, 1997Jun 27, 2001Eastman Chemical CompanyBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
EP1111099A2 *Aug 19, 1997Jun 27, 2001Eastman Chemical CompanyBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
EP1111100A2 *Aug 19, 1997Jun 27, 2001Eastman Chemical CompanyBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
EP1111101A2 *Aug 19, 1997Jun 27, 2001Eastman Chemical CompanyBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
EP2546395A1Jul 15, 2011Jan 16, 2013Kelheim Fibres GmbHRegenerated cellulose fibre
EP2546396A1Jul 15, 2011Jan 16, 2013Kelheim Fibres GmbHFibre bundle
EP2546397A1Jul 15, 2011Jan 16, 2013Kelheim Fibres GmbHRegenerated cellulose fibre
EP2706133A1Sep 7, 2012Mar 12, 2014Kelheim Fibres GmbHMethod for manufacturing viscose fibres
WO1989001062A1 *Aug 1, 1988Feb 9, 1989Courtaulds PlcCellulosic fibre
WO1997023248A1 *Dec 20, 1996Jul 3, 1997Mcneil-Ppc, Inc.Improved absorbent body
WO1998007909A2 *Aug 19, 1997Feb 26, 1998Eastman Chemical CompanyBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
WO1998007909A3 *Aug 19, 1997Jun 4, 1998Eastman Chem CoBundles of fibers useful for moving liquids at high fluxes and acquisition/distribution structures that use the bundles
WO2001001908A1 *Jun 30, 2000Jan 11, 2001Johnson & Johnson GmbhTampon for feminine hygiene and process and apparatus for its production
WO2013010759A1Jun 26, 2012Jan 24, 2013Kelheim Fibres GmbhRegenerated cellulose fiber
WO2013010760A1Jun 26, 2012Jan 24, 2013Kelheim Fibres GmbhFiber bundle
WO2013010761A1Jun 26, 2012Jan 24, 2013Kelheim Fibres GmbhRegenerated cellulose fiber
WO2014037191A1Aug 13, 2013Mar 13, 2014Kelheim Fibres GmbhProcess for producing viscose fibers
WO2014201484A1Jun 13, 2014Dec 24, 2014Lenzing AgHighly absorbent polysaccharide fiber and use thereof
Classifications
U.S. Classification428/398, 428/397, 264/188, 264/209.1
International ClassificationD01F2/10, D01F2/06
Cooperative ClassificationD01F2/20, D01D5/24, Y10T428/2975, Y10T428/2973, D01D5/253, D01F2/10
European ClassificationD01F2/10, D01F2/20, D01D5/253, D01D5/24